Most of existing vehicle black boxes is recording the surroundings of a vehicle by using a built-in camera. The vehicle black boxes are recently being developed to additionally record the driving history and the audio from an accident site. The driving history recorded in the vehicle black box may include a running speed of the vehicle, a rotation angle of the steering wheel, and so on.
Up to the present, such vehicle black boxes are mainly used to record images of the vehicle's surroundings for detecting an accident occurrence or a traffic violation of the driver. Recently, the vehicle black boxes are also being used for recording the indoor circumstances of a vehicle. The use of vehicle black boxes recording the indoor circumstances of the vehicle is increasing. Therefore, it is necessary to protect the privacy of the passenger captured in the images.
In order to protect the privacy of the passenger captured in the images, a technique partially masking the image and storing the masked image is widely being used. The privacy region-masking technique of the related art had been made mainly for a CCTV (Closed Circuit Television) camera. In other words, the privacy region-masking technique of the related art has not been developed for the vehicle black box. As such, the privacy region-masking technique of the related art cannot effectively detect a region to be masked and cannot protect the privacy from illegal use of the image.